Unless otherwise indicated herein, the description in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section.
There is provided an image forming apparatus such as a multifunctional peripheral (MFP) that can print a document and an image. In this image forming apparatus, a recording sheet to which a toner image is transferred is heated by a fixing unit to fix the toner so as to perform image formation. As a method for heating this fixing unit, there is a method using induction heating (IH).
Here, as a conventional method of the induction heating, there is known a non-contact power transmission apparatus. The non-contact power transmission apparatus includes an oscillation circuit and performs alternating-current driving of a primary-side winding based on the output of the oscillation circuit to convert the alternate current induced in a secondary-side winding that faces the primary-side winding into a direct current so as to transmit the electric power. In the non-contact power transmission apparatus, the oscillation circuit is constituted by a variable-frequency oscillation circuit with a variable drive frequency, and the input electric power to be supplied from a power supply to the primary-side winding is detected to find the drive frequency at which the input electric power becomes maximum. The oscillation circuit is operated at this drive frequency.